Thermal behaviour of the air inlet
To manage the temperature at the sensor to work in any season
The position of the shutter of the humidity sensitive air inlet is directly determined by the value of the relative humidity measured at the level of the sensor. However this value can be different from the one measured in the centre of the room in which the air inlet is installed, because for the same absolute humidity, the relative humidity varies according to the temperature. It is then easy to understand that the temperature at the sensor of the air inlet has an essential role on the read relative humidity. It is thus fundamental to control this temperature, in order to control the position of the shutter whatever the climatic conditions (indoor and outdoor temperature, indoor and outdoor relative humidity) and to adapt it directly to the indoor emission of humidity.
The importance of a "good" thermal coefficient
The thermal coefficient CT is determined by the formula: Tsensor = CT x (Tindoor - Toutdoor)
Where T = temperature in degree C
Several years of research made it possible to determine and control an ideal value of coefficient CT. With a coefficient CT of 0.25, the Aereco humidity sensitive air inlets offer a great amplitude of modulated flow for every season, and are ready to react to the least emission of interior moisture. In winter, in a room where the relative humidity is low, the shutter is in closed position, ready to react and to open for any emission of humidity. With a higher coefficient (around CT = 0.3), as it is the case for the majority of the other humidity sensitive air inlet of the market, the temperature of the sensor is too low in winter ; it thus reads a too high relative humidity which causes a too important default opening of the air inlet, even when the water content is low in the room. Its capacity of modulation is then very reduced, and the thermal losses are increased. Too low temperature of the sensor can even go until causing an important increase of hysteresis (difference between back and forth on the curve of opening/humidity), which then does not make it possible to determine the position of the shutter for a known relative humidity.